Joel and Ethan Coen claim they never saw the first “True Grit,” helmed by Henry Hathaway and released in 1969, earning John Wayne his only Oscar.

At least, that’s what they told production designer Jess Gonchor and costume designer Mary Zophres, advising them not to bother with the earlier film, but to focus instead on the Charles Portis novel on which they based their script.

“At our first meeting they said, ‘Don’t watch it,’ ” Gonchor recalled.

He followed the advice, although he admits he later snuck in some YouTube viewings of parts of the first film. Zophres also took her cues mainly from the book, which she read three times before reading the Coens’ script.

The Coens are more interested in creating their own mythology than in doing remakes or producing pictures that fit the mold of traditional Hollywood fare.

“There’s something not exactly real about the look of their movies,” said Gonchor, whose work on “Grit” is his fourth collaboration with the duo. “They’re not hung up on replicating things.”

After reading the script for “Grit” and talking about it with the Coens, Gonchor went off and did his own research on the film’s period, the 1870s, and came back to them with drawings, images and concepts.

“I know them pretty well and can tell how they respond to something,” he said. “If they push a piece of paper around the table, they’re not warming up to the idea. But if they’re warm to the idea, I’ll know right away that I’m on the right track.”

Gonchor added that he always tries to get the two of them together in meetings.

“It’s just easier. If I talk to them separately, eight of 10 times it’ll be the same answer, but there have been times when they haven’t both agreed on something right away.”

Other than the Coens, Gonchor works most closely with d.p. Roger Deakins, who has shot many of their films, starting with “Barton Fink” in 1991. “I’ll go to any length to make Roger happy,” he said.

On “Grit” they faced the challenge of arranging and lighting landscapes under harsh weather conditions. Gonchor points out that production design applies to exteriors just as much as it does to interiors. For the film’s climactic standoff at a ridgetop campsite, he and Deakins resorted to clearing trees to alter the vista below.

“For that scene I went to the top of the ridge, took pictures and photoshopped out what we wanted removed, and gave it to the guys who went out and cut down the trees.

Probably more than most directors, the Coens have worked with members of the same team over the decades. “We’re like a family or club,” said Zophres, who first worked with them on “Fargo.” “We joke about our idiosyncracies and obsessions, and we have a shorthand because we’ve worked with one another so much.”

Like Gonchor, Zophres uses the Coens’ scripts as a springboard to bring original ideas to the story.

“The scripts speak to me,” she said. “I immediately intuit a visual of how it should look, and I know what they’re going to like.”

For example, after considering plaid and other options, she dressed LaBoeuf, played by Matt Damon, mostly in fringed buckskin. “He’s the dandy of the bunch,” she said, “like a fish out of water, and I wanted to make him stand out.”

As for Bear Man — garbed in bear hides in the book and script — Zophres interpreted him as a “modern-day homeless man” and suggested a more menacing appearance, enveloping him entirely in a full bear skin, complete with its head as his startling hat.

Gonchor points out that a Coen brothers film gets a lot of mileage out of a limited budget. “What I’m most proud of is what we pull for the amount of money we have, which is nothing. I just did a commercial for Budweiser and we had a bigger art department budget for a four-day shoot than for this feature.”

Based on last weekend’s numbers, “True Grit,” with a reported production budget south of $40 million, was on track to gross more than $100 million domestically, besting all Coen brothers films at the B.O.